Monday, April 22, 2013

Ice, Ice, Baby

Today we spent another day on the eastern side of the Peninsula, and it is much, much colder now than earlier in the cruise. Today it was about -10 degrees Celsius, or about 14 degrees Fahrenheit. Everything keeps freezing outside, including all of our equipment. It makes things interesting! We were chased out of one area because of some bad weather, but we got to take another ice core before we left and saw a cute seal sunning himself on the ice. The helicopters were flying that day and luckily made it back in time before the really bad weather hit, but it was close! The landings were a bit tricky, but the pilots we have are very good at what they do.

Sea ice starting to form once the temperature dropped.

Since it is so cold now, we have been able to see sea ice form really quickly on the surface of the water. It is amazing how fast it can freeze once it gets cold and the wind starts blowing. First, a really thin layer of ice forms on the surface, and you can see it really well, because the water looks very calm and slick in that area. Then pancake ice forms, which really looks like pancakes, and then it just keeps getting thicker and thicker throughout the night. In a matter of 30 minutes a few inches of ice can form, and coat the entire surface of the ocean for as far as the eye can see. Pretty amazing!

Pancake ice forming on the surface of the water.

Yesterday, we picked up a piece of scientific equipment, called a mooring, near the coast. This instrument is kind of like a fancy buoy, but it stays slightly under the water at a certain depth and can stay in one spot for many years at a time. This particular mooring has been in its spot for almost exactly a year; the scientists on board dropped it off last year around this time. This instrument has been taking measurements such as salinity and temperature for that whole year, and it also had sediment traps attached to it in order to catch any of the particles falling through the water column towards the sediments. The traps are really interesting, because you can get an idea about the kind of phytoplankton, and other invertebrates such as krill that might be living in this area. We saw some cool little critters in those traps!

Sediment trap from the mooring with cool critters!

Today was a busy day of science and getting water samples, but tomorrow the weather should be good and the helicopters can fly to the glaciers again. Usually when the helicopters are gone we can not do much else on the ship, because they want to make sure all of the crew members are ready in case anything happens with the helicopter flights. Safety for these flights is the first priority of the ship during that time. It is ok for us though, because it leaves more time for sight-seeing and penguin spotting :)

3 comments:

Good question! In some places in Antarctica, the ice accumulates for thousands of years. The ice forms in layers like tree rings or sediments, but ice is also a little different from sediments because it flows. The oldest layers of ice are in the bottom layers, and once they have many layers on top of them, they get compressed and often start to slowly flow. This makes it more difficult to date, and take measurements from the deepest layers. Otherwise though, yes we can date the ice back thousands of years (by many different methods), and we can estimate things like the temperature back then, the concentration of CO2 in the atmosphere, and even how windy it might have been by measuring the amount of iron in the ice from wind-blown dust. Pretty cool! The ice cores we were taking on this cruise are much smaller than those type of ice cores, ours are only about 3-4 years old. These are interesting too though, because the temperature and the ice shelves have changed very rapidly in Antarctica over the past 3-10 years. Thanks for asking!